The Curiosity rover has been scooting around one of the garden spots of ancient Mars — a lakebed where conditions were favorable for life. And while the lake's water probably vanished billions of years ago, if anything ever lived there, clues could be lurking below the surface.

The rover landed in Gale Crater. Its instruments found that much of the crater floor is coated with clay, which forms in a watery environment. What’s more, the water wasn’t too salty or too acidic — it would have been just right for microscopic life like that on Earth.

But Mars’s gravity wasn’t strong enough to hold on to the planet’s atmosphere, so much of it wafted off into space. And without a thick atmosphere, there was no way for liquid water to exist on the surface. Some of the water combined with other compounds to form clays and other types of rocks. Some formed the planet’s polar ice caps. And some may have filled underground reservoirs — some of which could still be around.

There’s no evidence of life itself at Gale Crater or anywhere else on Mars — at least so far. But Curiosity is continuing to explore its Martian garden spot for hints of life in the planet’s watery past.

And Mars is in great view tonight. It rises above the Moon in late evening, and sticks close to the Moon as they climb across the south in the wee hours of the morning. It looks like a brilliant orange star.

We’ll talk about the Moon and another bright companion tomorrow.

Script by Damond Benningfield, Copyright 2014

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